Recent content by DougJohnson

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    ADS-B DIY Antenna

    How was your dongle connected before? Thanks, Doug
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    ADS-B DIY Antenna

    Right now, my spider is connected to the amp with about 20" of coax. The amp is connected to the dongle with about 6" of coax. The dongle and amp are connected to the Pi with about 4" of USB cable. All the electronics are inside a baggie tie wrapped to the mast and feed by 15' of USB cable...
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    ADS-B DIY Antenna

    Twisting with a drill works just fine. Get your wire, fold it in half, chuck one end in the drill and the other in a vise, pull it fairly tight, and twist away. -- Doug
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    ADS-B DIY Antenna

    One of the appeals of the Franklin for me was that it was DC grounded. I assume that has fewer static build up problems. Not so with the spider. I have seen a number of suggestions including a reasonably high value resistor (say 1K to 10K), an inductor, or back to back diodes from the 1/4...
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    ADS-B DIY Antenna

    It occurs to me that my last reply may have sounded curt. If so, I apologize. For background, I ordered this low noise amplifier (LNA) a couple of months ago: http://lna4all.blogspot.com/ I was attracted to it because of high gain (18 db at 1090Mhz), small size, and 5v power. The plan was...
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    ADS-B DIY Antenna

    I was walking down the street and a mailman handed it to me. Nope. The amp is easy and I've waited too long. I suspect the spider and the amp will show everything out to the horizon anyway. I did look at the Franklin and find the tap is not where I had measured the optimum. Perhaps it got...
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    ADS-B DIY Antenna

    That's why I chose the fiberglass rod. I just cut off a piece of it. It is not painted, the color is in the resin and goes all the way through. I popped it in the microwave and it does not heat. I can move the antenna to a wooden dowel, but my amplifier finally showed up so that will be the...
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    ADS-B DIY Antenna

    Good thoughts on my poor Franklin. I'll take some measurements and microwave a piece of the rod as soon as I can, but life is coming at me right now. In a good way. Thanks, Doug
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    ADS-B DIY Antenna

    I've been silent for a week or so, working on my 6 element Franklin. I fixed the broken wire and put it up where I could get to it easily and started tuning the tap. I moved the tap back and forth, each time logging the signal strength, maximum distance, average hourly message rate, and...
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    ADS-B DIY Antenna

    I assume we would need to allow for the velocity in both cases. The coax I am using is about .69 and bare copper is .95. So I should adjust the lengths accordingly? -- Doug
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    ADS-B DIY Antenna

    According to the man page: http://unixhelp.ed.ac.uk/CGI/man-cgi?dmesg+8 dmesg just prints the boot time messages. By the way, you don't need "sudo" for it. I get the same last line when I run it. I assume it is just showing the amount of paging space being allocated. -- Doug
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    ADS-B DIY Antenna

    What kind of difference did it make relative to the bare CoCo? Thanks, Doug
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    ADS-B DIY Antenna

    I was speculating that this morning. Thanks for confirming. -- Doug
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    ADS-B DIY Antenna

    1) Unless you have an overloading problem, the diplexer hurts not helps. 2) The balun is a big help. -- Doug
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    ADS-B DIY Antenna

    My 8 element CoCo is my second best after the spider. The spider is back up now. I discovered a broken wire on the 6 element Franklin. So we can throw out all the previous complaints. Now we'll see if I get the energy to build another. Probably. Especially if Jepolch has some good...
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